Aliso Canyon Update

Recent & Upcoming Activities

SCAQMD Provides Community Update of Input Received on Draft Scope of Health Study – PRNC meeting, Feb 12, 2018

SCAQMD staff have been invited to the Porter Ranch Neighborhood Council meeting to provide the community an update and summary of the input received on the draft scope of the health study.

  • Presentation – “Update and Summary of Input Received from the Community on Draft Scope of Health Study” (PDF) – Feb. 2018  New!

SCAQMD Releases Final Air Monitoring Results Report

This technical report summarizes the air monitoring results from all fixed-site and mobile measurements conducted by the SCAQMD in Porter Ranch and other neighboring communities between October 2015 and July 2017.

Community Meeting to Request Input on Draft Scope for Health Study - Dec. 14, 2017
The SCAQMD held a community meeting to request input on the draft scope for the health study related to this incident.

  • Meeting Flyer (PDF)

  • Presentation - "Options for Health Study of Impacts of Well Rupture at Aliso Canyon" (PDF)

  • Worksheet (Fillable PDF) – All input on the health study was requested by Jan. 31, 2018

Additional Air Monitoring and Inspection Activities

On July 31, 2017, SoCalGas (SCG) resumed natural gas injection operations at its Aliso Canyon storage facility.  As one of the conditions for resuming injection activities, aerial measurements of methane emissions from the facility were conducted by a third party contractor earlier that week. Airborne surveys on July 27 and August 3, 2017 revealed the presence of increased methane emissions from the northwest portion of Aliso Canyon.

In response to this finding, starting on July 28, 2017, SCAQMD staff from the Office of Compliance & Enforcement and Atmospheric Measurement were dispatched to investigate the cause of these elevated aerial measurements, and mobile methane surveys resumed within and outside of the SCG property line, to include within The Termo Company (Termo), and in the surrounding communities. While inspectors and atmospheric measurements staff detected, identified, and verified repairs of specific leaks from various components at both Termo, and SCG, so far, no obvious emission sources associated with renewed injection operations have been detected by SCAQMD staff. 

Mobile surveys in Porter Ranch and other neighboring communities have consistently shown methane readings close to typical ambient levels. SCAQMD will conduct additional mobile surveys and follow-up inspections at both Termo, and the SCG Aliso Canyon facility, and in the surrounding communities. The latest mobile methane survey results and updates will be posted on our website.

Executive Summary on Air Monitoring Results
A document summarizing the air monitoring results from all fixed site and mobile measurements conducted by CARB and the SCAQMD between October 2015 and June 2017 can be found here. A more detailed discussion on these air monitoring results will be provided in a companion technical report that is currently being finalized.

Order for Abatement
On January 18, 2017 the Hearing Board held a hearing to extend the Order for Abatement to September 30, 2017.  For more information, please visit Order for Abatement.   

Settlement Agreement
News Release - SCAQMD Reaches Settlement with SoCalGas for $8.5 Million for Aliso Canyon Gas Leak - February 8, 2017 (PDF)


Minor natural gas leak reported by SoCalGas July 2, 2016

Shortly after 2:00 p.m. on Saturday afternoon, July 2, 2016, SoCalGas notified SCAQMD of a “minor non-hazardous [natural gas] leak indication" discovered by SoCalGas personnel during a routine inspection of Well SS-10.  SCAQMD inspectors were dispatched to the site immediately to investigate.  No natural gas odor complaints associated with the site were reported to SCAQMD by the public, and SCAQMD inspectors were unable to detect natural gas odors in the surrounding community.   SoCalGas excavated an area near Well SS-10 and confirmed that the leak originated at a threaded coupling on a natural gas pipe running ~18 inches below the ground surface and adjacent to the well.  SCAQMD inspectors detected and recorded the leak using a FLIR camera and collected an ambient air sample using a SUMMA canister.  SoCalGas depressurized the line and began making repairs, which were completed by 9:30 the following morning (Sunday), shortly before SCAQMD inspectors returned to the site for follow-up. 

SoCalGas determined that the buried pipe with the leaking component led from the facility’s on-site gas processing plant to injection/withdrawal Well FREW 5. According to SoCalGas representatives, this line should not have been pressurized.  On further inspection, they found a leaking valve that was allowing natural gas to pass downstream.  When SCAQMD inspectors inspected Well FREW 5, they found that the well was not operational and had been disconnected.  Inspectors did not observe or detect emissions at Well FREW 5.


A review of ambient air data from SCAQMD fixed air monitoring stations in the Porter Ranch community before, during, and after the time the leak was discovered and repaired showed typical readings, with a maximum hourly methane level of 2.15 ppm, indicating that the leak had no appreciable effect on methane levels in the Porter Ranch area.

Aliso Canyon natural gas well sealed

Southern California Gas Company (SoCalGas) operates the Aliso Canyon natural gas underground storage facility at 12801 Tampa Avenue in Northridge, CA 91326. On October 23, 2015 SoCalGas discovered that Well SS25 used to inject and withdraw natural gas from the underground storage reservoir at their Aliso Canyon facility was leaking.  On February 18, 2016, the California Department of Conservation, Division of Gas and Geothermal Resources (DOGGR) provided notice to the public confirming that Well SS25 at the Aliso Canyon Gas Storage Facility has been successfully sealed.

South Coast Air Quality Management District (SCAQMD) and California Air Resources Board (CARB) staff jointly developed a set of criteria to determine when air quality in the surrounding communities of the Aliso Canyon facility has returned to typical conditions -  a checklist to determine when the air quality is no longer being impacted as a result of the leak.  Click on the following links for information about:

SCAQMD staff continues to observe and monitor operations at the Aliso Canyon facility and the surrounding community and to conduct ambient air measurements both within the facility and offsite in Porter Ranch and surrounding communities.  SCAQMD will continue to monitor ambient air levels and provide updates on this website. 

Information about other actions SCAQMD has taken in response to the natural gas leak from Well SS25 is available at the links below:

Compliance/Enforcement Activities


Report odors similar to the sulfur (rotten egg) smell of natural gas to 1-800-CUT-SMOG (1-800-288-7664) or through the On-line Complaint System.  If  you otherwise believe there is a problem related to natural gas, please also contact SoCalGas at 1-800-427-2200.

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